#include <bits/stdc++.h>//万能头
#include <iostream>

using namespace std;//命名空间
int a, b; //定义2个变量a,b
int main() { //main函数
	cout << "Hello World!" << endl;
	cout << 123 + 321 + 456 << endl; //计算
	cout << "123+321+456 = " << 123 + 321 + 456 << endl; //输出
	cin >> a >> b; //输入变量a、b
	cout << a + b << endl;
	return 0;
}
